1. Generally speaking, the solar altitude angle decreases gradually in autumn, and the temperature decreases gradually; The autumn wind is cool, the summer heat is gone, the fruits are covered with branches, and the fields are golden.
2. Autumn is the harvest season, and many plants mature in autumn. In the subtropical region of the northern hemisphere, the temperature in autumn is obviously lower than that in summer. As the temperature drops, the leaves of many deciduous perennial plants will gradually change color, wither and fall off.
3. The main meteorological disasters in autumn are: autumn rain in West China, cold dew wind in the south, frost and chilling injury at low temperature.
Autumn is one of the four seasons. Meteorologically, the autumn in the north temperate zone is from August 23rd (summer) to165438+1October 20th (light snow). Autumn in the south temperate zone is from February 19 (rain in the northern hemisphere) to May 2 1 (xiaoman in the northern hemisphere).
Extended data astronomy:
In autumn, the direct point of the sun gradually moves south from the northern hemisphere, passes through the equator after the autumnal equinox, and the sun directly shines in the southern hemisphere. Seen from the northern hemisphere, the angle of the sun gradually becomes lower, and the gap between day and night becomes smaller. At the autumnal equinox, the length of day and night is equal. In autumn, the distance between the earth and the sun is from far to near. Seen from the ecliptic plane, the sun is on the background of Leo, Virgo and Libra.
Health:
Autumn is the best time to keep fit, so you should eat vegetables. Vegetables can not only preserve health, but also help treat some diseases. In dry autumn, you should eat more green leafy vegetables, because it has high vitamin content, so it is good to eat more. Dark vegetables such as spinach, green vegetables, celery, chrysanthemum, amaranth, carrots, etc. Like brown-red vegetables, they are rich in vitamins and carotene.
Baidu Encyclopedia-Autumn